Posts Tagged ‘Erin Simmons Fitness’

I received quite a bit of feedback, both good and bad, on my last commentary on CrossFit. Some things I discussed with people one on one, some people trolled the page, and some people actually learned something new! However, there still seem to be some misunderstandings and misconceptions that I want to clear up. I have put together a list of some of the most common arguments, statements, and comments that I received on my position on CrossFit and I address them below.

But first, I’d like to quote Dr. Kenneth Jay, who received similar feedback from Crossfitters to some of his articles. His words of wisdom: “No emotional attachment.” As he reminds us, “[B]e willing to abandon your opinion—because in science, you are not entitled to your own opinion; you are only entitled to what you can argue for.”

Finally, my education levels and experience were called into question by numerous Crossfitters. Let me clarify: I have a Bachelor of Science and a Master of Science in Biology. I worked for the Department of Defense in a physiological laboratory for a military experimental unit. I am second author on a paper published in the Journal of Applied Physiology dealing with exercise performance, physiological responses to stressors, heart rate, VO2/VO2 max, and diving physiology. I am currently working on my Ph.D. in an integrated exercise physiology and sports nutrition program at Texas A&M. In addition to my own collegiate athletics career as a student athlete, I am starting my third year as a volunteer assistant coach for multi-year national championship track and field teams at A&M. I work with athletes in strength development, conditioning, rehabilitation, and event-specific training. I not only work with top-level athletes, but also with top-level, world-renowned coaches, doctors, and training staff. I know that I don’t know everything. I have a lifetime of learning ahead of me. But I’ve also been in great positions to absorb the knowledge of people who have already spent their lifetime dedicated to becoming experts in their respective fields. I’ve been able to read, discuss, assimilate, and synthesize their knowledge of exercise physiology, proper training techniques, injury prevention, injury rehabilitation, workout periodization, workout progressions, athletic training, and much more.

So without further ado, I address some common issues people had with my article:

It’s better than people doing nothing. Aren’t you happy to have them off the couch?

I love that CrossFit gets people excited about fitness. I love that it fosters a community of people working out together and motivating each other. Does that change my opinion about its programming (or lack thereof)? Absolutely not. The benefits of getting people off the couch are outweighed by the stress that is being put on their bodies. The potential for injury in CrossFit is drastically increased when newbies jump into it, especially if their coach’s certification and knowledge is questionable.

Let’s say there is an overweight person sitting on a couch. When they are sitting on that couch, they have lots of options they can take to improve their situation. If they jump into CrossFit and sustain an injury that puts them back on the couch, the options they have are now limited. For some people who have experienced extreme injuries like rhabdomyalysis or stroke, their lives may be drastically changed and they may never be able to exercise again. These are obviously extreme examples, but the concept is applicable to any degree of injury. There are far safer and more efficient ways to get people off the couch and work them into routines that will better target their goals than a cookie-cutter WOD at extremely high intensity.

I saw so much improvement from doing CrossFit. It changed my life!

Of course you did. If you go from doing nothing to doing something, you’re going to see results. Studies have shown that untrained individuals show favorable responses to nearly any protocol implemented, and their gains are often at a very high rate (6, 8, 12). You could have achieved this result from nearly any exercise program. Why did CrossFit work so well for you, then, when you didn’t personally see results from anything else you tried? The answer is found in the community aspect of CrossFit: you were accountable to someone, you had fellow sufferers, you had a community with which to compare your numbers and times.

The conclusion from this phenomenon, then, is that any benefits that you notice from CrossFit as a novice that you did not perceive in other training regimens is purely social and derived from a greater commitment to your exercise program. In the absence of that social factor, science tells you that initial physiological responses are essentially the same for any training program of choice (14). So why not apply that same commitment to one that is tailored to your needs and goals, while keeping safety a priority?

My gym is different. My coaches teach proper form and stop me if I’m doing it wrong. My gym has an intro program everyone has to go through before they can do the WODs. If you haven’t trained at my gym, you can’t comment.

I can, because CrossFit has a very distinct style of training to which most gyms adhere. If you’re doing CrossFit then you’re doing the WOD’s, which are posted on the main CrossFit website each day, or something very close to it. I can make the generalization because CrossFit has key similarities in its workouts that make up its fundamental flaws: lift many times, lift quickly, don’t rest, keep going until you can’t anymore. This is totally encompassed in the CrossFit term, AMRAP: as many reps as possible.

While this may not be an issue for a minute or two of push-ups or pull-ups, it becomes a big deal when it’s Olympic or Power lifts. Why? Because, as Kraemer et al. (12) state, “total-body exercises such as the power snatch and power clean have been regarded as the most effective exercises for increasing muscle power because they require fast force production to successfully complete each repetition”. This means that these exercises require a great deal of force on each rep in order to perform them correctly, which cannot be maintained for high volume sets such as those listed below:

Example WODs (from 2014 CrossFit Games qualifying rounds):

WOD 1: Complete as many reps as possible in 8 minutes of (Men/Women):

135/95-lb. deadlifts, 10 reps

15 box jumps, 24/20-inch

185/135-lb. deadlifts, 15 reps

15 box jumps, 24/20-inch

225/155-lb. deadlifts, 20 reps

15 box jumps, 24/20-inch

275/185-lb. deadlifts, 25 reps

15 box jumps, 24/ 20-inch

315/205-lb. deadlifts, 30 reps

15 box jumps, 24/20-inch

365/225-lb. deadlifts, 35 reps

15 box jumps, 24/20-inch

WOD 2: 60 clean and jerks (135 / 95 lb.). Time Cap: 7 minutes

Workouts like those listed above are asking the body to try to hit peak force for more repetitions than what the physiology of the body allows. For example, Chiu et al. (5) found that subjects exhibited decreased movement velocity, decreased peak force, and decreased rate of force development after just four sets of five repetitions of speed squats. If your rate of force and peak force decrease after just 20 reps of speed squats, with rest intervals, how can you expect to maintain fast force production over 30, 40, or 60 consecutive snatches or cleans?

Another study by Skurvydas et al. (21) showed greater low frequency fatigue and subsequent reduction in optimal positions in subjects performing 100 drop jumps compared to 50 drop jumps, concluding that greater magnitude of exercises causes a deterioration in form and increase in muscle fatigue. Which means that if you’re doing the WOD, or anything like it, you are putting excessive stress on your body via sub-optimal form, accumulating fatigue effects, and lack of planned recovery time. While each individual is different due to genetics, such a workout scheme over time will cause the body to break down. The question, then, is not will it have an effect on your body, but rather how longwill it take to have an effect on your body? You may bully your body through a battle or two, but it is a war you will ultimately lose.

People just need to be smart about how they do the CrossFit workouts. People should evaluate their gym and their coaches and make sure they know what they’re talking about.

When you have people who have perhaps not worked out their entire lives or who have been casual gym-goers, you can’t assume that they know the right questions to ask, the right way to warm up, how to recognize signs of fatigue, when their form has deteriorated, or the smart time to stop the workout. A good training method recognizes this and ensures that its instructors are adequately trained to educate their members on these subjects and assist them with applying these subjects to their training. A good training method meets people where they are and helps them get where they need to be without throwing them immediately into the deep end. Studies have shown that trying to do too much too quickly leads to fatigue and overtraining because the body is not able to physiologically adapt to the stress (4). The result is typically extreme soreness and/or injury (14).

Any good training method should be concerned with injury prevention and take measures to ensure that participants are properly evaluated before performing workouts to determine whether or not they are ready for the intensity of the prescribed workout. Any good training method should allow flexibility for those who have not yet adapted or adjusted. A good training method does not assume the participant knows proper progression. Successful training programs are dependent on program design, proper instruction, setting goals, evaluation, correct exercise prescription, and progression aimed at individual-specific goals (12). The general principles of progression are purposeful variation, specificity, and the gradual increase of stress during training, so that demands on the neuromuscular system are progressively increased and not immediately shocked and shot (12, 14).

Two predominant types of overtraining in resistance exercise are too high intensity and too high volume (15), which are both integral parts of CrossFit. Thus, there is no smart or safe way to do a CrossFit workout except to drastically alter it, in which case it’s technically not CrossFit. Classic CrossFit training is fundamentally wrong according to current scientific standards and methodology in the field of strength and conditioning. I have a really big problem with the above statements and the way that the CrossFit culture seeks to push all responsibility onto the individual members. They charge the average person with trying to find a good coach, asking the right questions about certifications, evaluating the workouts, evaluating themselves and their level of fitness, and evaluating the level of safety of workouts and boxes. Due to the multitude of information and misinformation in the fitness world, these are unreasonable expectations to have of the general public when their health is on the line.

There are good and bad coaches in every sport, not just CrossFit.

Well of course. I don’t deny that at all. But the “fad” aspect of CrossFit has allowed it to grow too quickly and has made it easy for beginners to start coaching beginners. The biggest barrier to entry into the CF world is not time or training, but money. I’m not saying there aren’t bad personal trainers, but a personal trainer is likely not teaching you to Olympic or power lift with large amounts of weight and/or for speed.

Kraemer et al. (12) points out that these lifts “require additional time for learning and proper technique is essential.” The exercises and workouts that CrossFit employs drastically increases the danger that comes with having a bad coach. The importance of having a qualified and knowledgeable coach is summed up by Pearson, et al. (14), who point out that “(t)he effectiveness of any training program is defined by the ability of the strength and conditioning specialist to effectively use scientific principles as the basis for making a multitude of decisions on a day-to-day basis as to the individual progression of a resistance-training program for an athlete.”

I understand that some coaches and boxes are better than others, but it should be a corporation-wide requirement with oversight that does not currently exist. CrossFit, Inc., in an effort to evade liability and allow “free market function”, has essentially said that this task is neither their problem nor their responsibility and that they will play no role in quality control. Instead, founder Greg Glassman has been quoted as saying, “Crossfit can kill you” as well as stating, “We have a therapy for injuries at CrossFit called STFU (shut the f*** up)”.

Such blatant disregard for the safety and well-being of Crossfitters is wholly inexcusable! Why let your body take the beating of being a cash-cow to a pyramid business scheme that ultimately does not have your best interest in mind? Why allow yourself to be taken advantage of in order to benefit others? The point to exercise and athletics is to achieve health, fitness, and performance; therefore any properly developed training program should be 100% based on a concern and care for the individual and should be carried out with a mindset of selfless service.

At the end of the day, it is the workouts that I am ultimately concerned with: lack of personalization, lack of programming, lack of progression, too high reps, too little rest, and a focus on speed of completing exercises rather than quality of the exercise. These types of workouts, coupled with the probability of a coach with a weekend certificate, make CrossFit particularly dangerous.

All sports and athletic activities have a risk of injury. CrossFit isn’t any different. So should we not play football or run either?

It does not mean that at all. Of course there is risk of injury in each sport, and even in the world of general fitness. However, you cannot compare apples and oranges by comparing CrossFit to athletics. In order to compare injury risks, you would have to compare the injury rates in the strength and conditioning training for those sports. Athletes in sports such as football or track spend time in the weight room and on the track or field practicing and training in order to prevent injury during their actual performance and cause neuromuscular adaptations. Strength training in athletic programs specifically targets weaknesses that lead to injury and underperformance. The difference is that CrossFit tries to make a sport out of this training, instead of viewing it as a method of injury prevention. By making strength and conditioning training into a competition of how many lifts you can do or how fast you can do them, CrossFit compromises these training goals and instead makes the participant susceptible to injury.

Additionally, athletes recognize the risk that comes with competing in their sport at a very high level. These people aren’t just trying to get “fit” by competing, they are trying to be in the top percentile of their sport and many times they are trying to earn their living by doing so. Are there very high rates of injury among football players? Absolutely. But I’m not taking an average person off the couch or out of the local gym and putting them in pads and sending them out into a game to get them in shape. I’m not going to grab a mom of three and put her in a track meet to run sprints or hurdles to get her to lose some baby weight. But CrossFit takes these people and puts them into high intensity programs with complex lifts and high reps of auxiliary exercises, whereas elite athletes develop over years and years of building on past progress while being guided by highly trained professionals. That’s the difference.

You said you can’t use weights to increase cardiovascular performance, but it gets my heart rate up so it has to help my VO2/VO2 Max!

In my first article I quoted a comment made by Dr. Kenneth Jay, a Danish neurophysiologist (I apologize, my first article said he was Dutch, which was incorrect; find his bio here), regarding lifting weights for cardio. He details his points further in the following posts on his website, Fast Force First (Part 1, Part 2).

Essentially, yes you can get your heart rate up using weights. However, increasing your heart rate does not correlate directly to increasing your VO2 or VO2 max (3). If this was the case, Dr. Jay says he could “scare you into shape”! Lifting weights fast does not result in the same training effect as typical cardiovascular exercises such as running, cycling, or rowing. Pearson et al. (14) outline this concept as well, stating “resistance-training programs do not typically improve maximal oxygen consumption to the extent that other modes of cardiovascular training do”. In fact, it is possible to have detrimental effects from spending too much time under tension, such as during high volume weight training. Dr. Jay explains that, over time, the excessive contraction of the thoracic Vena Cava not only leads to a lower VO2 but can also result in the thickening of the heart wall and a higher resting heart rate. To quote Dr. Jay, “This is NOT healthy!”

You have no scientific evidence on which to base your opinion.

Quite the contrary. Just because there are few papers that address the specific term, “CrossFit”, does not mean that scientific evidence for the detrimental effects of CF doesn’t exist. When you break it down to the fundamentals of CrossFit, you see that the style of workout goes against basic principles of exercise physiology that have been around for decades. Few papers have addressed CrossFit specifically for two reasons: (1) it is relatively new and it takes time to put studies together and get them published, and (2) physiologists likely don’t see a need academically to specifically address CrossFit because there is already a great deal of work showing that the fundamentals of the workouts utilized by CF are detrimental and not ideal for proper training, especially for athletes.

Here are some basic training principles that are ignored or violated by CrossFit WODs and training methods:

Periodization

As Pearson et al. (14) state, “The essence of periodization is the variation in load, volume, rest periods, and exercises done in a consistent manner over time.” Many studies have supported the concept that systematic variation of volume and intensity is the most effective training protocol, and that periodized programs result in greater changes in strength, motor performance, total body weight, lean body mass, and percent body fat than non-periodized programs (6, 11, 12, 22). There is a need for variation in volume and intensity to increase fitness and minimize fatigue (4, 12). Fatigue after-effects are cumulative, so that stressful training without sufficient recovery results in systemic fatigue effects, especially in the immune system (4). Classic CrossFit does not periodize or strategically vary workouts, and does not trade off between volume and intensity.

Progression, Programming, and Individualization

The body must be given “appropriate” stressors in order for the neuromuscular system to adapt (3). What is “appropriate” varies for each individual, so that maximizing the effectiveness of a strength training program requires its individualization after performing a health screening and needs analysis. This analysis should include health/injury concerns, appropriate frequency, muscle group strengths and weaknesses, etc. (12). Proper resistance training involves the manipulation of variables both throughout each workout and over time, including: muscle actions, resistance, volume, exercises, workout structure, sequence of exercises, rest intervals, repetition velocity, and frequency of training (12). There is also an inverse relationship between volume and intensity, and it is better to use higher volumes at the start of a training plan and gradually modify (4, 12). It is also recommended that multiple joint exercises, such as snatch, clean, and push press, be performed early in a training session when fatigue is minimal (12). Classic CrossFit does not follow proper programming during workouts, implement progression over time, and does little to modify for individual needs, goals, or weaknesses.

Multiple Sets

With a goal of maximizing strength development, multiple sets per muscle group have been found to be superior to single sets (10, 11, 16, 20, 23, 24). During the first 6-12 training sessions (or 10 weeks), an individual may benefit from single-sets but multiple-sets are significantly superior thereafter. Additionally, no studies have shown single set protocols to be superior for trained or untrained individuals (6, 8, 12, 14). Greater magnitudes of exercises, which are common when performing single sets, have also been found to result in slower muscle strength recovery, taking 7 or more days after exercise to return to normal strength levels (21). CrossFit, however, utilizes single set protocols for multiple WODs, such as the popular “Isabel” as well as the workouts listed previously in this article. Such workouts do not allow for muscle recovery during or following the workout.

Rest Intervals

The ability to sustain consistent repetitions over consecutive sets in weight training is dependent on the length of rest interval, which must be long enough to recover ATP (energy) and clear fatiguing substances (H+) so that force production can be restored and maximum strength development is enabled (2, 9, 17, 19, 23, 24). Greater strength increases have been showing utilizing longer rest periods of 2-5 minutes as compared to 30, 60, and 90 seconds (12, 15, 18). The American College of Sports Medicine (1) especially stresses the need for rest periods in multiple joint lifts (i.e., snatch, clean, push press), for which 3-5 minute rest intervals are recommended. CrossFit does not implement specified rest times and often discourages resting by prescribing workouts that encourage as many reps as possible in a given amount of time, or by requiring lifts and ancillary exercises be completed in as little time as possible.

Training and Recovery of the Neuromuscular System and Avoiding Overtraining

While these concepts go along with periodization and programming, they are more specific to the neuromuscular system. Periods of reduced volume are necessary for neuromuscular system to recover and to avoid overtraining muscles (14). Following exercise, the body experiences both fitness and fatigue effects, each to varying degrees depending on the type of workout performed. Fitness effects following training allows for improvement and up-regulation of peripheral and central nervous systems; fatigue after effects are both neural (down-regulation of nervous system) and metabolic (depletion of energy sources – ATP) (4, 13). The fatigue effect accumulates over time, and as it increases, the adaptive ability of the individual decreases, resulting in overtraining (4). So what causes such a fatigue effect? According to Pearson et al. (14), too much volume for too long of a duration is one of the key factors in overtraining. CrossFit requires a large volume of lifts and exercises be done on a consistent basis, with no planned period for recovery. High intensity and high volume are staples of classic CrossFit, and both are scientifically shown to result in overtraining (14).

In conclusion, there has been much scientific work that addresses the fundamental flaws and resultant safety issues associated with CrossFit. From lack of individualization to overtraining, there is a scientific basis for the argument against CrossFit and its random, “one size fits all” methodology. Exercise physiology is a complex topic to which I hope I have brought some clarity for the readers of my initial article. My goal here isn’t to inflame people; my goal is to educate and to have a conversation about something that many people may not want to talk about. Many people don’t know the risks associated with CrossFit, and I want people to be able to make an educated decision. Ultimately, though, it is each person’s decision to make, and if the person accepts the risks and the stress that his/her body will have to endure, then that is the individual’s choice. I love that CrossFit has been able to forge a cohesive community that is excited about working out, however, we have to make sure that our desire to be a part of something does not overcome our powers of reasoned thought.

For those of you who don’t know, I really enjoy doing obstacle course races. Not just any obstacle course race, mind you, but Spartan Race. These races are tough, challenging, and push you hard, but the best part is the amazing support system that Spartan offers. They post Workouts of the Day, Foods of the Day, motivational quotes, and offer practice sessions to “rip you off your couch”, as they tout in their slogan. They offer multiple races to target whatever level you may be at, with the Spartan Sprint (3-5 miles), Super (7-9 miles), and Beast (12+ miles). For the more adventurous, there’s the Ultra Beast (double the Beast course) and the Death Race. For the last two years, I’ve done the Texas Beast and plan on making it a yearly tradition, recruiting more friends each year to hit the course with me!

So are you ready to Spartan Up? Are you ready to get “ripped off the couch”? If you’re ready to challenge yourself to do things you never thought possible, whether that doing 30 burpees in a row or winning your age group, then you need to check out Spartan Up! Spartan Race founder Joe DeSena has collaborated with Jeff O’Connell on this brand new book. The book isn’t available until May 13, but you can check out the synopsis now and pre-order the book on Amazon. I read over the synopsis myself, and generated some questions for Joe in an interview that is coming soon! But I also wanted to share a few thoughts after reading the synopsis, so here are some of the main points I’ve identified as thought-provoking, interesting, and important:

Spartan Up! embraces three main concepts: Question your Assumptions, Less is More, Discipline is Everything.

Self Control

“Our self-control pales next to the Spartans. I’m convinced they would have looked at us with disgust and disbelief.”

People think they can’t attain lofty fitness goals, but anyone can IF they keep in mind that it is truly a “way of life”. So many people want results NOW. So many companies advertise the shortest amount of time to see results. Some companies advertise that you won’t even have to put work in. But a real athlete and competitor knows that it takes a LONG TIME of working REALLY HARD to reach your ultimate goals. That’s why I believe it’s important to set “stepping stone” goals along the way to keep you hungry and satisfied at the same time.

Learning from Failure

You won’t always have successes. Sometimes, maybe even most of the time, you will experience failures. How will you cope? Will you make it a learning experience or will you let it bring you down?

Importance of Obstacles

“As Marcus Aurelius, the philosopher king portrayed in The Gladiator, noted: ‘Fire feeds on obstacles…and inversely dies without them.'”

What can an obstacle course teach you? It can help you recognize your limits, learn when to hold on and when to let go, when to ask for help, how to be a good teammate, how to analyze a situation, and how to move on after failures.

Battle of the Mind

Spartan Races aren’t just for your body. You strengthen and quicken your mind as well. Decisions made in the mud, with barbed wire pressing into your back, in cold weather and cold water help you make decisions efficiently in other areas of your life.

“History’s elite warriors have known that to win on the real battlefield, you must first win on the battlefield of your mind.”

The Spartan Race is aptly named, and reminds us of the Spartan philosophy that to “win on the real battlefield, you must first win on the battlefield of your mind.” The Spartan Race makes you think. Makes you analyze your situation. Makes you doubt yourself at times. But ultimately, it helps you win, whether that’s your age group, your battle with weight, in the classroom, or on the job.

Perspective

“If you find the prospect of navigating mud swamps, hill climbs and walls to be daunting, imagine tackling them from the confines a wheelchair. Yet Michael became the first paralyzed individual to ever finish a Spartan race.”

This shows us that everyone has a story. Everyone has their own personal obstacles. But seeing people like Michael help us put our problems, challenges, and setbacks into perspective.

Discipline

“If freedom is what you are after, it comes not from discipline, but through discipline.”

“Most people waste much of their days simply by not being organized and planning ahead.”

People often say they just don’t have time to workout every day, yet I’ve never seen a schedue that absolutely doesn’t allow it. If you are organized and driven enough, you wil make time.

Attitude

“Can attitude be taught? I believe it can. The way to create great attitudes is to push through adversity. Once you have seen the dark side, everything looks brighter.”

Is it your body that needs to be changed? Or is it your attitude? You may have to start with the latter first.

Fit not Fancy

“Our philosophy is that all you need to be fit is intestinal fortitude and a will, and that equipment shouldn’t be the difference maker.”

Many people think you can’t be fit without a gym, but that’s simply not true! The Spartan Race is an extremely challenging test of your physical fitness, and you can train for it anywhere. The necessary equipment for most of the Spartan workouts include your body and maybe a rock or branch to use for weights or pull up bars. Spartan workouts literally leave you with no excuses not to do them.

Life

“Why do a competitive race? Because you might be just dogging it through life.”

Finally, one of my favorite quotes from the article is the following, that “life was not worth living unless you were going to live it fully.”

So view the synopsis, grab the book, and sign up for a race. It’s time to get moving. Spartan Up!

This meal is relatively easy to make but takes a little bit of time, around 30 minutes. You can increase or decrease serving size, but the recipe below will make approximately 4 servings. This meal supplies lots of vitamins from the veggies as well as good fiber, and there are plenty of whole grains in the pasta.

-2 Chicken breasts

-2 or 3 cloves of garlic (based on personal preference)

-1 zucchini, sliced and quartered

-2 whole carrots, sliced

-1 green or yellow bell pepper

-1/2 small can black olives

-1 can organic primavera sauce

-Whole grain Farafalle pasta (3/4 is one serving, so based on desired servings, you can make as much or as little pasta as you would like)

Directions:

Cut the chicken breasts into 1″x1″ chunks and sautee in olive oil and Italian seasoning with the garlic (sliced or minced, to preference) in a large saucepan.

Once the chicken is nearly cooked through, add the veggies and cook until tender.

Add pasta sauce and black olives and simmer for 10-15 minutes.

While chicken and sauce is simmering, cook the pasta.

Mix both together or pour sauce over the top of the pasta. You can sprinkle parmesan or romano cheese over the top (in moderation of course!).

Like this:

Here is another ESF workout for you! This one is a circuit training exercise that is centered around lunges, but works in abs and arms stations as well. Guaranteed to make your glutes, hammys, and quads sore the next day! To make this workout harder, you can add weight to your lunges using either dumbbells or barbell of desired weight, and to your ab workouts by using a medicine ball.

Remember: For lunges, you should never let your front knee extend over your ankle and bend only until both knees are at 90 degrees! Otherwise you risk injury, especially if you are adding weight.

Just Google “fat burning zone” and the handy dandy search engine will pull up enough conflicting opinions to confuse a rocket scientist. There has been much debate as to whether more fat loss occurs at low intensity or high intensity training. Unfortunately, many people and fitness companies (and even personal trainers!) cite 24 Hour Fitness and the like as their “sources” of information, which are often opinions of their instructors and not necessarily based on real science literature. Such sources seem to think that since you burn more calories in general at higher intensities that you will then lose more weight. This is technically true, if you don’t care what kind of weight you lose. The fact is, most people would prefer to burn fat rather than burn muscle. Why? Because fat is unhealthy and unsightly, whereas muscle not only adds to our strength, but also requires much more energy to function during day to day activities. Which means that even when you’re not working out, your muscles are burning through calories, which is great for weight loss! Fat, on the other hand, is “in storage”, so think of it as your reserve fuel. Your body doesn’t want to burn through its reserve fuel if it doesn’t have to (the body is operating on survival instincts even though most of us don’t have to worry about whether or not we are going to get our next meal!), so you have to force your body to use that fat. It takes longer, lower intensity workouts to makes your body stick to fat burning. That’s why at the gym, you may notice that the cardio machines (i.e. elipticals and bikes) that have the heart rate monitors will give you a fat burning range that is much lower than cardio training range. When you’re working out and your body needs energy, it pulls it from wherever it can get it, whether that is carbs, fat, or muscle. Obviously, you want to maintain and/or build your muscle mass, keep your carbs for energy, and burn off your fat, right?? In order to do this, it has been scientifically shown that you should stay at lower levels of cardio intensity to target fat metabolism.

Be warned: what is about to follow is relatively lengthy and has direct summaries from scientific literature. If you don’t want to read all that, you can skip what’s in italics and go right to what is in bold, which is my plain-English summary of the “scienc-ese” summary. You can trust my interpretation because I have been reading scientific papers since I started my degrees (B.S. and M.S. both in Biology) years ago, and also because I am currently a Department of Defense contractor working in a Navy Physiology Lab! So I know my science, but feel free to read as much or as little of either my interpretation or the scientific abstract as you want.

The primary objective of this study was to examine the relationship of the “fat burning” and aerobic zones. Subjects consisted of 36 relatively fit runners (20 male, 16 female) who completed a maximal exercise test to exhaustion on a motor-driven treadmill. The lower and upper limit of the “fat burning” zone was visually assessed by examining each individual graph. Maximal fat oxidation (MFO) was determined to be that point during the test at which fat metabolism in fat calories per minute peaked. The lower limit of the aerobic zone was assessed as 50% of heart rate reserve, whereas the upper limit was set at anaerobic threshold. Although the lower and upper limits of the “fat burning” zone (67.6-87.1% maximal heart rate) were significantly lower (p < 0.05) than their counterparts in the aerobic zone (58.9-76.2%), the considerable overlap of the 2 zones would indicate that training for fat oxidation and training for aerobic fitness are not mutually exclusive and may be accomplished with the same training program. Furthermore, it was determined that this training program could simultaneously meet the requirements of the American College of Sports Medicine for both aerobic fitness and weight control. Maximal fat oxidation occurred at 54.2% maximal oxygen uptake (VO2max). However, the great variability in response between individuals would preclude the prediction of both the “fat burning” zone and MFO, indicating a need for measurement in the laboratory. If laboratory testing is not possible, the practitioner or subject can be reasonably confident MFO lies between 60.2% and 80.0% of the maximal heart rate.

So basically this study showed that while the upper and lower limits of fat loss and aerobic capacity do overlap, the maximal fat loss is at 50% of your VO2max! If you’ve ever been tested for your VO2max, you’ll know that 50% is not very intense (I have done the test here at the Navy Physiology Laboratory where I work). In fact, it’s estimated to be between only 60 and 80% of your maximal heart rate!

Physically active individuals generally show a reduced risk of coronary heart disease (CHD) compared to the sedentary population. However, whether such reduction in CHD risk mainly results from the concomitant improvement in cardiorespiratory fitness or from the alterations in CHD risk factors has yet to be clearly established. Furthermore, there is still some controversy regarding the potential associations between endurance training-induced changes in metabolic variables considered as CHD risk factors (plasma glucose, insulin and lipoprotein levels) and the magnitude of improvement in cardiorespiratory fitness. From the results of several studies discussed in this article, it is proposed that prolonged endurance exercise of low intensity (˜ 50% V̊o2max), performed on an almost daily basis, seems to significantly improve metabolic variables considered as CHD risk factors through mechanisms that are likely to be independent from the training-related changes in cardiorespiratory fitness. The notion of ‘metabolic fitness’ is introduced and can be defined as the state of a set of metabolic variables relevant to CHD risk and affected by the level of physical activity. Evidence available suggests that these metabolic variables are not closely related to the adaptation of cardio-respiratory fitness in response to exercise training. The concept of metabolic fitness has several implications for the prescription of exercise and for the primary and secondary prevention of CHD. Indeed, emphasis should not be placed on aiming at increasing V̊o2max through high-intensity exercise, but rather on producing a substantial increase in daily energy expenditure that will eventually lead to weight loss and related improvements in carbohydrate and lipid metabolism. Therefore, from a practical standpoint, although a 1 h daily walk may not have marked effects on cardiorespiratory fitness, it probably represents an exercise prescription that is likely to substantially improve ‘metabolic fitness’, thereby reducing the risk of CHD.

This one is slightly different because it is looking primarily at combatting coronary heart disease. However, they do show that metabolic fitness, defined as “substantial increase in daily energy expenditure that will eventually lead to weight loss and related improvements in carbohydrate and lipid (lipids = fats) metabolism”, is achieved at 50% of the VO2max as well. So this confirms what the other study found as well in terms of the maximal fat metabolism threshold.

Purpose: The aim of this study was to develop a test protocol to determine the exercise intensity at which fat oxidation rate is maximal (Fatmax).

Method: Eighteen moderately trained cyclists performed a graded exercise test to exhaustion, with 5-min stages and 35-W increments (GE 351 5). In addition, four to six continuous prolonged exercise tests (CE) at constant work rates, corresponding to the work rates of the GE test, were performed on separate days. The duration of each test was chosen so that all trials would result in an equal energy expenditure. Seven other subjects performed three different GE tests to exhaustion. The test protocols differed in stage duration and in increment size. Fat oxidation was measured using indirect calorimetry.

Results: No significant differences were found in Fatmax determined with the GE35 /5, the average fat oxidation of the CE tests, or fat oxidation measured during the first 5 min of the CE tests (56 + 3, 64 + 3, 58 + 3%VO2max respectively). Results of the GE35 65 protocol were used to construct an exercise intensity versus fat oxidation curve for each individual. Fatmax was equivalent to 64 + 4%VO2max and 74 ± 3%HRmax. The Fatmax zone (range of intensities with fat oxidation rates within 10% of the peak rate) was located between 55 ± 3 and 72 ± 4%VO2max. The contribution of fat oxidation to energy expenditure became negligible above 89 ± 3%VO2max (92 + 1%HRmax). When stage duration was reduced from 5 to 3 min or when increment size was reduced from 35 to 20W, no significant differences were found in Fatmax, Fatmin, or the Fatmax zone. Conclusion: It is concluded that a protocol with 3-min stages and 35-W increments in work rate can be used to determine Fatmax- Fat oxidation rates are high over a large range of intensities; however, at exercise intensities above Fatmax, fat oxidation rates drop markedly.

This study shows slightly higher values of the maximum fat utilization, though their exercise time is much shorter than other studies. They found a maximal fat burning zone between 55 and 72% of VO2max (with a maximum at 64% VO2max or 74% maximal heart rate). They also showed that fat contributes negligible amounts of energy over 89% VO2max or 92% maximal heart rate, which is often where high intensity workouts keep you.

Stable isotope tracers and indirect calorimetry were used to evaluate the regulation of endogenous fat and glucose metabolism in relation to exercise intensity and duration. Five trained subjects were studied during exercise intensities of 25, 65, and 85% of maximal oxygen consumption (VO2max). Plasma glucose tissue uptake and muscle glycogen oxidation increased in relation to exercise intensity. In contrast, peripheral lipolysis was stimulated maximally at the lowest exercise intensity, and fatty acid release into plasma decreased with increasing exercise intensity. Muscle triglyceride lipolysis was stimulated only at higher intensities. During 2 h of exercise at 65% VO2max plasma-derived substrate oxidation progressively increased over time, whereas muscle glycogen and triglyceride oxidation decreased. In recovery from high-intensity exercise, although the rate of lipolysis immediately decreased, the rate of release of fatty acids into plasma increased, indicating release of fatty acids from previously hydrolyzed triglycerides. We conclude that, whereas carbohydrate availability is regulated directly in relation to exercise intensity, the regulation of lipid metabolism seems to be more complex.

This one shows that as you increase intensity, more muscle breakdown occurs. They also found that utilization of fatty acids for energy decreased as intensity increased, plus fatty acids continued to be used at a higher rate even after exercise was complete! That’s good news, huh?

—————————————————————————————————————————————

As you can see, there isn’t much debate as to whether or not there is a fat burning zone, and that this zone is at relatively low intensities. All you have to do is read the back of a protein shake like Muscle Milk to see that the whole point of its existence is to repair muscles after high intensity training like weightlifting. If your body didn’t break down muscle during high intensity workouts and continue to do so even after the workout, there would be no need for these formulas! So what if you want to not only burn fat but also improve your cardiovascular fitness? Well, as Article #1 states, they are not mutually exclusive. In order to maintain a good balance between cardio training and fat burning, it may be beneficial for you to have a couple days that you do long cardio workouts at lower intensity to burn fat, while other days are dedicated to high intensity cardio training for shorter periods of time. As one of the articles pointed out (#2), even walking was sufficient to reach a fat burning heart rate! This means that even if you can’t make it to a gym every day of the week, you can still do something to keep your metabolism up and running. Sono excuses! Now that you have all the info, get to work on building your better body in 2012!